A warranty period optimization strategy considering the change point of infant failure rate

The point that the failure rate of a product tends to be steady and low from the high infant period is called change point. An ideal starting time of a warranty period should be exactly set as this point. The infant period of a life cycle is usually believed to be highly relative with the defects and failures which originated in production. However, due to the lack of studies on the mechanism of product infant failures, existing warranty policies usually assign the warranty periods without considering the change point of infant failure rate. To optimize the warranty policy and reduce the cost of product providers, the impacts of the usually overlooked manufacturing potential defects in the lifetime of a product is introduced in this paper at first. Second, a method to detect the change point by monitoring the tendency of the shape parameter of Weibull distributed products is introduced. Third, based on the identified change points of the infant failure rate, an optimization strategy of the warranty policy and the corresponding warranty cost model is derived. Finally, the model is verified by a warranty optimization example.